We propose to renew a Career Enhancement Core that focuses on providing predoctoral and postdoctoral fellows with high-quality research mentoring that will prepare them for careers in tobacco regulatory science research. The Core is primarily located at the University of Vermont (UVM), but also has postdoctoral fellows placed at our two collaborating sites, Brown University and Johns Hopkins University. All three institutions also have highly regarded T32 training programs in addictions research, which allows for rich cross-fertilization between tobacco regulatory science and addictions research. Consistent with the overarching focus of the UVM TCORS, this Core focuses on career enhancement around investigating use of tobacco and nicotine delivery products among vulnerable populations. The leaders of the Career Enhancement Core (Drs. Higgins and Heil) have a long history of effective collaborative mentoring in their roles as Director and Associate Director of the UVM T32 training program in addictions research. Eight additional primary mentoring faculty provide a wide range of expertise in the areas of vulnerable populations, addictions, behavioral science, and tobacco regulatory science research. Dr. Villanti bolsters our mentoring team's expertise in tobacco regulatory science. The Career Enhancement Core provides fellows with (a) hands-on research training in tobacco regulatory science in which they directly assist faculty with implementing the primary UVM TCORS studies while simultaneously leading pilot studies, (b) opportunities to participate in an ongoing, rotating seminar series on behavioral science, behavioral economics and behavioral pharmacology, research ethics, and tobacco regulatory science, and (c) abundant opportunities to present their research at national scientific meetings and prepare articles for publication in peer-reviewed journals. During the almost 4 years of the current funding period, we have mentored 14 predoctoral and postdoctoral fellows (4 predocs and 10 postdocs). Our fellows published 29 peer-reviewed articles supported by the UVM TCORS during the current funding period, including 15 as 1st author. In the current funding period, we have used pilot projects and developmental studies to ensure that fellows gain experience with independent research, collaboration, and grant writing in tobacco regulatory science. Going forward, the Core will leverage that experience and our growing expertise in tobacco regulatory science to establish the necessary infrastructure to prepare our fellows for successful careers in tobacco regulatory science, respond effectively to FDA rapid response and other initiatives, and to nurture partnerships and collaborations within the TCORS network. Overall, we feel that this Core is well positioned to continue and enhance its mission of preparing the next generation of tobacco regulatory scientists.